This invention relates to fuel injectors in general and particularly high-pressure, direct-injection fuel injectors. More particularly, high-pressure, direct-injection fuel injectors using a non-uniform plurality of slots in the swirl disk to produce a non-symmetric fuel cone.
It is known to use a high-pressure direct-injection (HPDI) fuel injector to spray fuel directly into the combustion chamber of an internal combustion engine. The amount of fuel sprayed by the fuel injector must be accurately metered. In addition, the fuel delivered to the combustion chamber must be properly atomized. In order to achieve proper atomization of the fuel, it is known to use a swirl disk to impart an angular velocity or spin to the fuel just upstream of an interface between the needle and the seat of the fuel injector. It is believed that a combination of the spin and the high pressure delivery from the fuel injector creates proper atomization in the form of a hollow cone of fuel exiting from the tip of the injector.
It is known that the geometry of the swirl generator determines the shape of the fuel spray exiting from the injector. It is known to use a symmetric swirl generator to create fuel spray in the shape of a symmetric hollow cone. However, specific applications can require a fuel spray in the shape of an atomized non-symmetric hollow cone, such as a hollow oval or shell shape spray. For these reasons, it is desirable to use a non-symmetric swirl generator to generate a non-symmetric conical fuel spray.
The present invention provides a fuel injector including a body having an inlet, an outlet, and a fuel passageway extending from the inlet to the outlet along a longitudinal axis. An armature is proximate the inlet of the body. A needle is operatively connected to the armature. A seat is proximate the outlet of the body. A guide member is disposed within the body, the guide member including an aperture that guides the needle. A flat metering disk is disposed between the seat and the guide member, the flat metering disk including a central aperture, a perimeter, and a plurality of slots. Each of the plurality of slots is disposed about the central aperture and extends from the central aperture toward the perimeter to define a volume. The plurality of slots are configured so that the volumes of two of the plurality of slots are non-uniform, and/or the plurality of slots are non-uniformly disposed about the central aperture
In a preferred embodiment, the plurality of slots includes a first slot, a second slot, and a third slot disposed radially around a central aperture. The first slot is disposed 60 degrees from each of the second slot and the third slot. The second slot is disposed 120 degree from the third slot. A length of the first slot is greater than a length of the second slot, and a length of the second slot is greater than a length of the third slot. A width of the first slot is greater than a width of the second slot, and the width of the second slot is greater than a width of the third slot. A fuel passage opening of the first slot has a diameter greater than a diameter of a fuel passage opening of the second slot, and the diameter of the fuel passage opening of the second slot is greater than a diameter of the fuel passage opening of the third slot.
The present invention also provides a method of delivering fuel from a fuel injector including flowing fuel tangentially in a non-uniform distribution through a swirl disk toward a seat, and metering fuel through the seat to provide a non-symmetric fuel cone.